Max mannesman



(Model.) u

MANNBSMANN MANUPAGTURB 0F SBAMLBSS TUBES. V No. 361,962. Patented Apr. 26, 1887.

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UNITED STATES PATENT OFFICE;

MAX MANNESMANN, VOF REMSCHEID, GERMANY.

MANUFACTURE OF SEAMLESS TUBES.

SPECIFICATION forming part of Letters Patent No. 361,962, dated April 26, 1887.

Application med April 1, iss?. serial No. 233,247;

(Model.) Patented in Italy January 26,1886, No. 7,925; in Luxemburg June 20,1886, No. 704; in Belgium August 14, 1686, No. 54,857; in Spain August 721, 1886, No. 9,537, and iu Austria-Hungary Septelnber 1S, 1886.

To @ZZ whom, it 17u03/ concern:

Beit known that I, MAX MANNEsMANN, of Remscheid, Germany, have invented certain Improvements in the Manufacture of Seamless Tubes of Copper and other Gomparatively vSoft Metals, of which the following is a specification.

This invention relates to a modification of the process of transforming solid blanks of soft and ductile metal into tubes, described in Reinhard Maunesmanns pending application, serially numbered 232,791, in which process diagonally-acting conical or conoidal rolls having convergent lines of impingement are employed in combination with a conical mandrel interposed between the rolls to drive a solid blank of comparatively soft and ductile metalagainst the point of the mandrel, and to force the metal displaced by the rolls to iiow over the surface of the mandrel, and to thereby transform the solid blank into a tube, the extern-al diameteriof which is less than the diameter of the blank, and is determined by the width of the space between the working-faces of the rolls where they most nearly approach each other.

4The object of the presentimprovement is to diminish the resistence which the blank encounters by its impact against the point ofthe mandrel, 'and thereby render it possible to produce by means of barrel-shaped rolls and a conical mandrel-of the desired size softmetal tubes having a greaterv external diameter than the width of the narrowest part of the space between the working-faces of the rolls, or even tubes having an external diameter greater than the diameter of the blank.

To this end the invention consists, iirst, in so arranging the relative angles of inclination of the diagonally-acting rolls and the length and the angles of convergence of those portions of their working-faces which operate to reduce the diameter of the blank as to impart to the portion of the blank uponv which they act a tendency to become hollow, according to the method described in the pending application of Max Mannesmann, No. 229,087; and secondly, theinvention embraces, broadly, the combination of diagonally-acting barrelshaped rolls with a conical mandrelthewhole 5o or any part of which is interposed between the diverging portions of the workingfaces of the rolls.

The mandrel, if desiredmay be made hollow, and may be kept cool by the circulation of water or other coolinglluid through its interior; but it will be found that a solid mandrel will answer perfectly for operating upon blanks composed of copper or other similarly soft and ductile metals or alloys, '6o

which do not require to be heated excessively hot.

The barrel'shaped roll-that is, a roll which is tapered at both ends and the working-face of which is preferably between two bearingsis preferred, principally because it permits of such arrangement that its bearings are equidistant from the path through which the blank travels. If, however, one of the bearings of the roll be arranged nearer to the path 7o the axial line of the mandrel-that is, on either side of the path through which the blank travels-their lines of impingement upon the blank will be relatively at rst convergent `8o and then divergent. Either of these forms of rolls are capable of being so arranged with relation to the blank that the twist imparted to the fibers during the process of developing the tubular formation may be wholly or partially taken out during the process of enlarging the tubular formation.

In the accompanying drawings, illustrating the apparatus employed, it is assumed that the .apparatus consists of two barrel-shaped rolls 9o which are arranged ou opposite sides of a conical mandrel affixed to the free end of a hori- -zontal shaft, the opposite end of which is supported in a standard or other stationary part of the apparatus, and that the axes of thebarrel-shaped rolls are inclined in opposite directions. A

As diagonally-acting rolling-machines are When a pair of either of these 75 well known, it is deemed sufficient to herein show only those operative parts of the apparatus which in their construction and mode of operation are comprehended in the presentA invention.

The drawings are as follows: Figure l is a top View of a pair of barrel-shaped rolls arranged on either side of the axial line of a conical mandrel, showing in horizontal section a solid blank which has commenced its passage between the rolls and by their impinging action upon it has had its forward portion reduced in diameter and ruptured or nearly ruptured in the line of its axis. Fig. 2 is a similar View of the apparatus, representing the blank at a further stage of its progress through the rolls, at which the forward end of the blank 4has acquired the tubular formation and is being compressed upon the smaller end of the mandrel. Fig, 3 is a similar View of the apparatus, and represents a still further stage of the operation, showing the complete development of a tubular formation of a greater external diameter than the diameter of the blank.

In the type of diagonal rolling apparatus illustrated in the drawings three, or even four, rolls may be employed in connection with a mandrel, and when more than two rolls are employed they serve to centralize the blank. It is preferred, however, to employ only two rolls, in which case the centralization of the blank is effected by suitable guides. As, however, the methods of supporting the blank in connection with two rolls are well known, it is not necessary to herein describe them in detail.

The operative parts illustrated in the drawings consist of the barrel-shaped rolls A a, which are respectively arranged on either side of the axial line of a conical mandrel, B, which projects into the space between -the working-faces of the rolls to such distance that its small end b is made to penetrate the central portion of the solid blank C after the blank has been engaged by the convergent portions A a' of the rolls, and has been thereby made to move forward and over the surface of the mandrel.

The mandrel-shaft B is stepped or journ aled in the standard D or in some other stationary part of the machine. The mandrel may either be permitted to revolve, or it may be held rigidly so that it cannot revolve. The effect of the action upon the solid blank of the converging portions A a of the rolls is to impart to it a tendency' to become hollow along the line of its axis.

rIhe rolls A a are by suitable gearing rotated in the same direction, and hence 'impart to the blank upon which they act rotation in the opposite direction. The speed of rotation thus imparted increases as the blank becomes smaller,4and is acted upon by portions of the rolls of greater diameter. There is therefore imparted to the portion of the blank acted upon a progressively-increasing twist.

In the act of reducing the diameter of the blank the metal at its surfaceis compressed and hardened, while the metal composing its central portion is not so compressed and hardened. The diagonal action of the rolls also has a stretching effect upon the metal upon which they impinge, tending to drive the metal toward and over the surface of the mandrel.

It results from the combined action of the forces to which the blank is subjected during its passage between the converging portions A a of the rolls that it acquires a tendency to become hollow by the rupture of its central portion along the line of its axis, and the metal from the center of the blank tends to move in a spiral. direction toward its periphery, in consequence of which comparatively small resistance is opposed to the penetration of the pointed end of the mandrel into the central portion of theblank. In some cases there may even be produced in the center of the blank a slight fissure, E, by the time the end of the blank has been carried far enough forward to reach the pointed end of the mandrel. It is not, however, necessary in dealing with comparatively soft and ductile metals or alloys that the blank should be actually ruptured before reaching the mandrel. Even if not ruptured, the tendency of the metal to move outwardly from the center, in obedience to the forces which have been described, diminishes the resistance opposed to the penetration into the center of the blank of the pointed end of the mandrel, and in either case the metal displaced by the impingement of the rolls upon the blank is forced forward with such energy that it is made to ilow over the base of the cone, and to thus assume theform of a tube, the internal diameter of which is approximately determined by the diameter of the base of the cone, and the thickness of its shell by the distance between the surface of the mandrel and the parts of the working-faces of the rolls which are nearest to the mandrel.

It will of course bc understood that the rolls may be so shaped that their lines of impingement upon the blank may be curved, and similarly the mandrel need not necessarily be perfectly conical, but may have its surface curved in the direction of its length.

It results from the comparatively small resistance of the center of the blank to the penetration of the mandrel, and the tendency of the metal under the action of the rolls to move spirally outward from the center of the blank that the mandrel is centralized, and thus the shell of the tube is made of uniform thickness, whether the external diameter of the tube be increased or not.

What is claimed as the invention isl. In apparatus for transforming solid metallic ingots or blanks into tubes, the combination, as herein set forth, of diagonally-acting barrel-shaped rolls, with a conical or conoidal mandrel interposed between those portions of the working-faces of the rolls whose lines of impingement upon the blank are relatively divergeht.

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faces of the rolls, by which the shell of the tubular formation thus developed is compressed upon the surface of the mandrel, whereby, owing to the relatively small resist-ance opposed to the penetration of the mandrel into the eenter of the blank, the mandrel is centralized therein and the shell of the tube is rendered 2o uniformjn tliiekness. A

MAX MANN ESMANN Witnesses:

A. M. J oNns, M. L. ADAMS. 

